That is the goal of rainwater harvesting, he said, it should go back into the water table if possible.

If it goes into the street and into the sewage drainage system, then it goes into the river and has to go through a water treatment plant before it can be used.

In 2008, he and his wife, Mary, went to a rainwater specialist training in which they learned how to effectively and safely harvest rainwater to be used for landscaping needs.

If a homeowner is looking to build a catchment system for his or her roof, he said adjustments need to be made to the gutters to transport the water to the the harvesting containers.

By using a simple equation, people can calculate how much rainwater they can collect depending on the area of their roof. For example, if the roof is 20-by 40-feet, the catchment area is 800 square feet. The volume can be calculated by multiplying the catchment area by the 0.62 gallons per inch rain per square foot, which would be 496 gallons per inch of rain.

"You can collect a lot of water that way," Meredith said. At his home, he has a 1,500-gallon tank that filled before the rain stopped.

Multiple barrels can be linked together, too, to collect as much water as possible, he said.

It's important for people to use a screen or lid on the top of their rainwater container to avoid the attraction of frogs, mosquitoes and other pests, said Martha Hamilton, office manager of Mosquito squad and certified applicator. There are many ways that she's heard people employ to protect against mosquito infestations including the use of vegetable oil, dish soap and pool chlorine tablets in rainwater containers.

"Adding a slick of vegetable oil on the surface will keep mosquitoes from water," Hamilton said. "I've also heard of people using goldfish in their barrels to eat the larvae."

Other options, she said, include treatment kits for rainwater barrels that can be found online or at the stores where rainwater barrels and catchment systems are sold.

Mosquitoes love wet and damp conditions, she said.

"It only takes a bottle cap full of water for a mosquito to lay eggs," Hamilton said.

Unless, of course, the intention may be to attract wildlife, including deer and birds, said Meredith. He has a wildlife dripper in his yard that dispenses a drop of water a second onto a small concrete container that will collect the water for birds and deer to drink from. Animals enjoy the running water, he said.

Building a rain catchment system can cost as little as $50, Meredith said. In its simplest form, a catchment system can consist of a large barrel or plastic waste drum. To use, fill a watering pitcher and use that way, he said. The more elaborate systems can outlets connected to drip irrigation systems or may include filtration systems.

Most catchment systems are used solely for landscaping needs, not drinking needs. If they are used in public, he said it's important to label them "Not for drinking."

"The best rain barrel you can have is an empty barrel," he said, "Because you can use it to collect water."

SHARE

To learn more

For more information about rainwater harvesting, visit the Texas AgriLife Extension Service rainwater harvesting website at rainwaterharvesting.tamu.edu.

Make your air conditioning work double duty

When it doesn't rain, it's possible to still collect water into a catchment system using an air conditioner unit, Paul Meredith said.

"You just have to divert that stuff from literally going down the drain," he said.

About $20 for the cost of PVC pipe and clear tubing can collect the condensation from the evaporator pan, which would otherwise go into the city's sewer system. With their 5 BTU air conditioning unit, he said he can collect 17 gallons of water every day.

They have a single barrel set aside outside to collect all the water from their air conditioning unit, he said.

Protect against mosquitoes

Mosquitoes can lay eggs in a small amount of water or moisture. Remember to empty water containers that might support larvae, Martha Hamilton said, and to turn compost piles.